Questions tagged [mathematics]
The abstract study of topics encompassing quantity, structure, space, change, and other properties
93
questions
0
votes
0answers
12 views
Input type error from raster calculation in ArcPy
I am trying to do raster calculation in ArcPy, which includes the application of expi (exponential integral function). Here is my code :
import arcpy
import scipy.special as sp
from scipy.special ...
0
votes
0answers
26 views
Calculate mercator map pixel size from viewport
What is the algorithm to calculate the pixel size of the entire mercator map.
Known information (see image):
Viewport's Upper-Left corner (Lat, long).
Viewport's Lower-Right corner (Lat, long).
...
3
votes
1answer
87 views
ECEF coordinates to geodetic coordinates: Where is error in calculation?
I know, there are several questions to this topic, but I am just searching for the error in my own equations. I have no deeper geodetic background, but I am trying to understand these formulas instead ...
1
vote
1answer
59 views
High resolution x,y dataset for Mollweide projection convert to latitude and longitude coordinates
I have a 2D array that's 144000 x 64000 that has some values that are irrelevant to the question. Let's say the array can be used like an X, Y coordinate system. I somehow need to get the Latitude and ...
1
vote
1answer
59 views
How to transform camera calibration parameters to other coordinate system?
I have all camera calibration parameters (X0, Y0, focal length, R0, P0, P1, K0, K1, coarse rotation, rotation, translation) and position of the image in WGS84 (XYZ in meters) and other parameters like ...
3
votes
1answer
45 views
Seeking documentation about non-iterative UTM to Lat-Long projection formulas
In
Hager, John W., James F. Behensky, and Brad W. Drew. "The universal grids: Universal transverse mercator (utm) and universal polar stereographic (ups)." DMA technical manual 8358 (1989).
I ...
1
vote
0answers
151 views
Calculating Center (GPS Point) and Radius (km) of n GPS points
I'm new to GPS and position mapping but i have a background in programing and some of the math related to it.
I've been tasked with writing a small golang program that takes n GPS points (DMS) and ...
1
vote
0answers
36 views
Converting latitude/longitude into a slab number (or item number) and vice versa?
Purpose: To compress the data transmission for the longitude and the latitude. Initially these datas are in the form DD.MM.mmmm: degrees, minutes, ten thousandths of a minute. Latitude stands under 28 ...
3
votes
0answers
100 views
Calculate weighted azimuth/bearing of a line
Given the line
LINESTRING(-9.086532643219698 -7.939337106873815,-1.396102955719698 -0.9775148048290135,-0.780868580719698 -0.7138718839794582,-0.077743580719698 -0.6699297767574899,0.581436106780302 ...
2
votes
0answers
369 views
Understanding cosine-weighting?
I am studying a paper where they use a method to calculate the vertical distribution of water content (ice, water vapor, cloud water) from the amount of ice on the martian surface.
In the paper they ...
1
vote
0answers
27 views
How is the Point on surface tool calculated in QGIS [duplicate]
I am interested to know how the Point on surface tool works in QGIS 3. I am choosing to use this rather than the Centroids tool which works of the "center of mass" methodology because this creates a ...
1
vote
0answers
65 views
Applying a two step floating catchment with boundary limitations
The literature states that gravity models and the two step floating catchment area (which in itself is a version of the gravity model) method for analysing the accessibility of healthcare services by ...
3
votes
1answer
64 views
How to run a Epanechnikov (parabolic) decay in QGIS 3.6 field calculator
Does anyone know how you would implement a Epanechnikov (parabolic) decay to a field in QGIS field calculator. I am trying to apply varying distance decay functions in order to assess the best ...
1
vote
0answers
189 views
calculating HRMS using NMEA sentences including GPGGA , GPGSV, GLGSV, QZGSV,QZGSA, GPGSA?
I have NMEA sentences including GPGGA , GPGSV, GLGSV, QZGSV,QZGSA, GPGSA and GNGSA. my goal is to achieve HRMS accuracy meter. produced android devices for special intent gives GP/GN GST nmea message ...
3
votes
1answer
190 views
Procedure of transforming coordinates?
I'm trying to understand the math behind this transformation. I should note that I've been able to perform the transformation using GeoPandas, but I'd like to understand what is going on under the ...
1
vote
0answers
45 views
How to compare centrality of points in different shaped and sized polygons
Suppose I have several polygons of varying shape and size, each containing a single point. I want to compare the centrality of each point, and determine which point is more central to its polygon. I'm ...
1
vote
2answers
1k views
Calculate angle between nodes or point in line in QGIS
I want to check the digitization of line in correct direction, so for that I need to know the angle of each node in line. Is that possible in QGIS?
3
votes
2answers
6k views
How to add meters to EPSG:4326 coordinates? [duplicate]
I've some lat/long in EPSG:4326 coordinate system like Eiffel Tower position : ["lat" : 48.858274,"lon" : 2.2944]
For automated tests I would like to get, for every points of my dataset, the x and y ...
1
vote
0answers
129 views
GRASS GIS: Getting know about stream power index (SPI) computation by r.watershed function
I need to know exact way how stream power index (SPI) is computed by module r.watershed. On the help page is that SPI is α * tan(β), where:
α is cumulative upslope area draining through a point per ...
2
votes
1answer
113 views
Postgresql - problem updating row with complex calculation
A calculation for the replacement value of a tree exists:
Variables:
index_price for species;
circumference of tree;
condition measures: vitality, root_injuries, stem_injuries,
crown_injuries
(A ...
1
vote
1answer
118 views
What's the math behind moving from a starting point in the direction of another one?
I am working with decimal-degree coordinates for a software and lack geographic background.
I want to convert the coordinates to a grid to calculate distances and then move around using standard ...
0
votes
1answer
71 views
Kriging: Large standard error very close to known value points
I am attempting to create surfaces of strata via Kriging in Arc GIS from borehole data. In addition to the predicted surface I also want surfaces showing 95% confidence above and below the predicted ...
1
vote
1answer
259 views
Formula for transforming from EPSG:4326 to EPSG:3003 or EPSG:3004
This system is used in Italy.
I came across this:
It says that lambda zero is 9° if it's to epsg:3003 otherwise if it's to epsg:3004 it's 15°
I came up with this Java code, but the result is wrong:
...
1
vote
2answers
3k views
Converting from ECEF to geodetic coordinates
I am trying to convert an ECEF coordinate to a geodetic coordinate using this procedure, but I don't fully understand the process. It is prefaced by stating the geodetic parameters {a,b,e,e'} are ...
1
vote
2answers
387 views
Calculate turn required to follow a line of latitude
Lines of latitude are not geodesic except at the equator. So to follow perfect eastern course in the northern hemisphere in a vehicle a left turn is constantly required. We can express a turn as the ...
3
votes
0answers
497 views
Calculate lat/long as percentage distance between two points (MSSQL)
I've loaded the US road shapes into MSSQL. I've determined the query to locate the segment of road for a specific address. The segment contains a "linestring" from a series of points.
I'm trying to ...
8
votes
2answers
508 views
Estimating resolution of vector data?
I got an old vector dataset with polygons covering a continent. The data was first published on paper at scale 1:5 000 000 and was later digitalized. I don't have the original data and no information ...
1
vote
1answer
3k views
Translating latitude and longitude into “polar coordinates” around a point
Times Square in New York City has the coordinates (as per Google Maps):
40.7589, -73.9851
The Barrymore Theater has the coordinates (again, as per Google maps):
40.7601, -73.9862
Given that ...
2
votes
0answers
2k views
Finding the Point of Intersection Between Two Line Segments and Level of Error
I am working on calculating the intersection of two lines. Each line segment is represented as two geographic coordinate pairs. Additionally, each line segment is less than 1km in distance.
My ...
2
votes
1answer
312 views
Creating local coordinate system from orthorectified image from drone
My plan is to use a drone and pix4d to map an area and produce a top down image. I have some position data that is in its own reference frame / Coordinate system.
My question is what suggestions or ...
4
votes
2answers
1k views
How can I calculate the coordinates of a point on the intersection of two parallel lines with a bisecting line with pyQGIS? [closed]
I am building some sort of homemade pyQGIS-Buffer-tool as the existing flat-end-buffer-tools are not working for me ( see v.distance.buffer does not create proper buffers with flat endcaps)
Therefore ...
2
votes
1answer
50 views
Determine on what side of a line my current position is at, no matter orientation
I know that this question has been up before, but I'll give it a shot since it's not exactly the same question.
Imagine a straight line consisting of a start point and an end point.
The orientation ...
2
votes
2answers
264 views
Getting lat/lng of an object X inches from the GPS? [duplicate]
I'm working on a project where I have a GPS and two receivers to create a triangle with a transmitter. The problem I'm trying to figure out right now is how can I get the position of the two receivers?...
2
votes
0answers
36 views
How to resolve a rectangle with know points? [closed]
How do I find the coordinates(lat, lon) for D and E in the following rectangle?
I know:
A (lat, lon)
B (lat, lon)
C (lat, lon)
AE, BE, AC
1
vote
1answer
648 views
Bearing to X,Y, Z
I’m working on a small project where I’m testing the ability of a laser to accurately measure the angle of a wire.
My control for the experiment gives me X,Y,Z coordinates for a point on the wire and ...
4
votes
1answer
778 views
How to generate missing points in GPS trajectories?
I have some GPS trajectories that include gps locations recorded on variable frequencies (every 1 min ,5 min , 20 min,etc.)using a geographic projection WGS84. In my work, i need a fine-grained GPS ...
3
votes
0answers
61 views
calculate turning acceleration from a compass
I have degree and timestamp and want to calculate the turning acceleration. What to trigger if the compass is turning fast.
Is there a mathematic way to get an acceleration parameter?
1
vote
1answer
186 views
Calculate location on line with known azimuth to point
I have the following situation (consider distances up to 300m - without great circle etc. affects):
How can I calculate the unknown location when I have all other locations in the triangle and ...
0
votes
1answer
57 views
Arithmetics with Coordinates [duplicate]
I wonder if I can do simple arithmetics with coordinates. Can I do substraction of coordinates like 2.570801 (lng) 46.89023 (lat) / 17.424316 (lng) 55.15377 (lat)?! Or will that get messy without a ...
5
votes
1answer
348 views
Index express the similarity in shape between two data sets
I have two data sets.
One is points in the blue curve. The other is points in the green curve.
Now I want to find a property (P) or something else like index that has the following characteristics:
...
5
votes
1answer
1k views
Finding Intersection of Two Circle given Lat/Lon and radius?
I am attempting to calculate the intersection of two circle on the Earth with a given latitude, longitude and radius. I started with this Calculating intersection of two Circles?
These circles will ...
2
votes
2answers
531 views
What mathematical processes does a GPS receiver use to determine position?
I'm writing a report on the mathematics of GPS, but I'm wondering what methods the GPS actually uses. What I've done is set up the four sphere equations and solve them using the Newton-Raphson method ...
9
votes
1answer
2k views
Project location on a (great circle) path
I've been searching this SE site for quite a few hours now, and I'm still struggling to find a solution to my question. My goal is that given a way in OSM and my location (lat/lon coordinates), I want ...
11
votes
3answers
5k views
Converting latitude, longitude (epsg:4326) into EPSG:3857?
I'm looking to study the math involved to see how a given latitude and longitude in decimal degrees can be converted to EPSG:3857. Can anybody point to a good reference or a possible Ppython/C/C++/...
2
votes
1answer
1k views
Check if a point coordinate is between linestring coordinates
I know that, linestring is a vector and if i want to check that, if point coordinates are between linestring beginning and ending coordinates then i need to use vector comparison
(x2 > x && ...
1
vote
0answers
181 views
How do I compute uncertainties in the positions transformed using Helmert transformation?
I am familiar with Python, MATLAB and Mathematica. My data is given by Cartesian coordinates (positions in X,Y,Z (meters), standard deviations XX, YY, ZZ (meters) and a correlation matrix (XY, YZ, ZX)....
7
votes
2answers
914 views
Aerial photogrammetry book with all the math
Can anyone recommend a book that hits all the math for the general situation of doing serious photogrammetry calculations on aerial photographs?
Particularly an inexpensive book or one I can get ...
3
votes
3answers
3k views
How to calculate the center and radius of a circle based on points
I have a set of lat/long points. I need to calculate the center point and radius of a circle that will encompass all the points.
The co-ordinate system used is latitude/longitude as per google maps.
...
1
vote
0answers
153 views
How to organize/cluster nodes moving on the same direction
The Problem
I am working on a problem of clustering for mobile nodes.
Initially, I though of clustering the nodes based on their angle of movement (relative to the x-axis). However this situation ...
2
votes
1answer
482 views
Comparing compass bearings
I have several compass bearings:
bTrue = 190°
b1 = 250°
b2 = 100°
b3 = 170°
b4 = 90°
I want to compare b1 - b4 and find out how close they are to bTrue. So bTrue is 100%. How much percent is then b1,...
